Seismic receiver motion compensation

Abstract

A method of compensating for seismic receiver motion in a marine seismic survey wherein at least one receiver is towed behind a moving seismic vessel comprises producing an acoustic energy wave at a seismic source, and recording the reflection arrival time t2 of the acoustic energy wave at the one receiver. The offset x between the source and the one receiver is determined. The normal moveout velocity V for the acoustic energy, and the velocity VB of the seismic vessel are also estimated. A corrected reflection arrival time t1 , of the acoustic energy wave is then determined by applying a time correction to the recorded reflection arrival time t2. The time correction is a function of the offset x, the normal moveout velocity V, and the velocity VB of the seismic vessel. The method is applicable to a plurality of receivers, whether the receivers are arranged in a single sensor acquisition system or hardwired to form receiver groups.

What is claimed is:  
     
       1. A method of compensating for seismic receiver motion in a marine seismic survey wherein at least one receiver is towed behind a seismic vessel, comprising: 
       producing an acoustic energy wave at a seismic source;  
       recording the reflection arrival time t 2  of the acoustic energy wave at the one receiver;  
       determining the offset x between the source and the one receiver;  
       estimating the normal moveout velocity V for the acoustic energy;  
       determining the velocity V B  of the seismic vessel; and  
       determining a corrected reflection arrival time t 1  of the acoustic energy wave by applying a time correction to the recorded reflection arrival time t 2 , the time correction being a function of the offset x, the normal moveout velocity V, and the velocity V B  of the seismic vessel.  
     
     
       2. The method of  claim 1 , wherein the one receiver is towed by the seismic vessel towards the source, and the corrected reflection arrival time t 1  is determined according to the equation: 
       
         
             t   1   =t   2   +x ( V   B   /V   2 ).  
         
       
     
     
       3. The method of  claim 1 , wherein the one receiver is towed by the seismic vessel away from the source, and the corrected reflection arrival time t 1  is determined according to the equation: 
       
         
             t   1   =t   2   −x ( V   B   /V   2 ).  
         
       
     
     
       4. The method of  claim 1 , wherein the source is an air gun. 
     
     
       5. The method of  claim 1 , wherein the one receiver is a hydrophone. 
     
     
       6. A method of compensating for seismic receiver motion in a marine seismic survey wherein a plurality of receivers is towed behind a seismic vessel, comprising: 
       producing an acoustic energy wave at a seismic source;  
       recording the reflection arrival time t 2  of the acoustic energy wave at each of the receivers;  
       determining the offset x between the source and each receiver;  
       estimating the normal moveout velocity V for the acoustic energy;  
       determining the velocity V B  of the seismic vessel; and  
       determining a corrected reflection arrival time t 1  of the acoustic energy wave for each receiver by applying a time correction to the recorded reflection arrival time t 2 , the time correction being a function of the offset x, the normal moveout velocity V, and the velocity V B  of the seismic vessel.  
     
     
       7. The method of  claim 6 , wherein the receivers are arranged in a single sensor acquisition system. 
     
     
       8. A method of compensating for seismic receiver motion in a marine seismic survey wherein a plurality of receivers is towed behind a seismic vessel, the receivers being hardwired to form receiver groups, comprising: 
       producing an acoustic energy wave at a seismic source;  
       determining the reflection arrival time t 2  of the acoustic energy wave at the center of each receiver group;  
       determining the offset x between the source and each receiver group center;  
       estimating the normal moveout velocity V for the acoustic energy;  
       determining the velocity V B  of the seismic vessel; and  
       determining a corrected reflection arrival time t 1  of the acoustic energy wave for each receiver group center by applying a time correction to the recorded reflection arrival time t 2 , the time correction being a function of the offset x, the normal moveout velocity V, and the velocity V B  of the seismic vessel.